Gramophone and the like



@di i Julie. 24,- 1930.

C. M. WALTER ET A'L GRAMPHONE AND 'IjHE L IK `Filed Feb. 5, 1929 3 Shets-Sheet 1 June 24, 1930. c, vM'. WALTER fr zu. l1-,`7(7,."s3o GRKMoPHoNiaiAND THE LIRE I y Filed Feb'. 5, 1929 s sheets-Sheet y2 Patented June 24, 1930 e TES CECIL MONTAGE WALTER, .on FOUR OAKS,Y ANntRIOnAnD GREGORY' MARSH, OF5' OFFICE BIRMINGHAM, ENGLAND Y GRAMOPHON' YAND THEKLIVKE i Appueatiqa med `February 5; 1929, serial 30.337,66@ and-in Great Braam February 5,1928;

This invention relates tof improvements-in gramophones and the like, and refers particularly to instruments of the vtype in which l mechanical vibrations setup in a stylus bar travelling over va record disoare converted into electrical vibrations by What is known f as an xelectrical pick-upampliied, and dis-f tributed as sound Waves by a loud-speaker- In the Ordinary type of gramophone em-` Eployi'ng a sound-boxfthe sound-box 4is car-1 ried at the free end of a swivelling hollow tone-arm, and as the tone-arm is necessarily comparatively short, the path-of the needle f carried by the sound-box'V is not truly radial with respect to the disc but is anarcof aA circle having the tone-arm as radius. -Itfol- I loWs thereforek that the sound-box and needle y can only be in correct alignment With'the 2 groove inthe reeord disc at one point, 'gene erallyk aboutthe middlel of the length' of the groove,fandexeessive 'vveai` ofthe record is caused towards the outer and'in'ner edges'of the record disc byside-thrust ofthe needle in jj the groove..`` Y l Y -r The object of our invent-ion is-to provide vmeans Wherebyin thecase'of 1an" electrical pick-up this fdefectca'n be entirely eliminated so that Wear on the reeord dis'cis reduced? to Q50 Aa minimum and substantially true `reproduc- I f Vtionfcan be obtained Withoutscratfoh'or'disil ltortion.

y V A furtherobjectis to eliminate or reduce to the shortest'possible'length theusu'alloose leads betvveu'i*the'pick-up` and iiXed terminals or other' contacts ,'on the gramophone body.

A Lvstll further:object; is to permit vthe Weight of thelpiekiup itself to be counterbalanced or compensated fory to any desired 4o. evtentj` so that the weight'appliedn' to the stylus can be ykept down to the'minimumre-` quired: to Y give correctfreproduction and eX- cessive Wear 'of the frecrddisca which isy i a common faultwi'th pick-ups, is eli'miAnated;v -These and Other'features of our inventionV Will bemade elearfin the particular descrip#` tionwith respect to the accompanying-draw;

Figure 1 is a sideelevati'on of One'formof pick-up` mounting 1n accordance With our invention which can gramophone. Figure 2is`an end elevation.V i

Figureq is a section'on the line 3 3 o l with the 'lug which carries the vpick-upy raised, and thepickup detached; a Figure tais a diagrammati'cside elevation of aV simple production.`V l l v Figure 5 is a similarside elevation `of a slightly heavier model. f

.Figure 6 isa side elevation ofa mounting similar to; thatl shown in Fig.` 1; but with Y certain parts made oiinsulatingy materiali y In the forinillustrated in Figs, 1, 2 "and 3, the Xed partfof the mounting 'consists .0f a cranked arm- 1 ot aluminium or like maf. terialhaving'atone enda peg 2 of triangular l or other section-adapted toJ fit into i and be `be `itted'to anyexisting u i i Y formof mounting for'cheaper l l extends-'-horizontallyl over the gramophone ets lfand 5, in which are mounted grooved turntable and ysecured into it are small braok- Y secured into an 'f insulating bush in the larm Vorjjthe reasons givenlbelovm v `The,pick-"upf8 Avvhichisf"of any" standard type' hasa'bayonet or other Vconnection l with a vsockety attheI reeend of a metal lug 9VA Whi'ehterminates a'titsfother endin a ldisc 10. The clisc is clamped between discs L11 andl 12 atftheendsiftvvolengthsof accurately ma-` bushes so that the lu`g'9 is in metallicconnec';

rod are'in 4exact alignmentso'fthat'in eeet they form' mechanically fone continuous, rod. The rod'is adaifte'd to` restin the grooves Vtact Withv the rod. The totali length." of` 'theA rod-#s that throughout the entirerange tion- With the part 13 of the'rod and insulated from the part 1 332l These tvvoipartsf of the f in therrqllersvfand 7 and'is held against re- I i movalzby stirrups 15 which are fout of conf l secured` abracket fseouredupon thebody [7..0 ,ofagraniophone ",'lfhefreeendof'the arm of movement of the pick-up the rod is supported by both rollers.

For changing the needle or stylus 16 of the pick-up, the pick-up, lug, and rod canl be rwung up around the axis of the rod into the position shown in Fig. 3 in which position it may be supported by a stop 17 on the'lug which engages the rear edge of the arm. v

Of the current leads from the pick-up one s earth'ed (iny the nietal socket as shown at 18 in Fig. 3. `The circuit of this lead is then through the lug 9 to the rod 13 and through the roller 6 with which the rod is in metallic contact and so to the arm 1 and to a ixed teriiiinal 19 thereon. i

The other lead 20 is taken through a bore in the lug 9 to a stud 21 in metallic contact with the rod 13. This rod is in metallic contact with the roller 7 on the insulated bracket "5 from whichV an insulated wire is taken through a bore in the arm lato an insulated terminal 22 adjacent to the terminal 19. By this arrangement the usual loose leads are eliminated and an extremely neat result is produced.

Vhen applying this mounting to an `existing gramophone a template is preferably provided fitting jover'the centre pin of the turn-table and giving the exact location of the 'fixing screws for the'base bracket 3. When the arm 1 is droppedinto this bracket the rod 13 will lie in a position parallel to a radius of the turn-table and at such a distancetherefromthat the needle jor stylus `on the pick-up `when in engagement withl a record disc-is constrained to move"- in a` truly-radial path lthereon through the simple .gravitational engagement of the rod in the grooves' of. the

rollers'. `While this relation exists no other movement is possible except arollingor ro?` tational movement about'the laxis of the rod which movement is permitted with aj minif mum of frictiony so lthat the pivotal action of Jrhe pick-up which allows it to ride freely "over any irregularities'ojr inaccuracies -of the record disc-isy obtained in the simplest possible manner. 1

'If lit. shoul .be found that the loadvonthe jtylus imposed bythe weight of the pick-up n, is greater thanisnecessaryfor good repro-- duction, the rod can be provided with counter-balance'weights which maybe carried on an extension Tof `the lug 9,.as shown in Fig. 3.

rllhe embodiment illustrated in. Fig; 4 is a" somewhat simpler form intended for easy applicationto existingfgramophones- In thisi case arod2;3 is secured atlts ends 1n lugs profor gramophones comprising la fixed sup-1 ]ecting forwardly :from ya rigidyhorizontal rm 24 adj ustably .clamped on aiixed pillar. The pick-upwis held ina clip Qn lthe end of an arm on La:bifurcated bracket25 on ,the arms ofV which are mounted grooved anti-friction rollers25f. adapted: to,- travelon the prod.

. riedV by the pick-up.

i The embodiment illustrated in Fig. 6 isV similar to thatillu'strated in Fig. 1 but in this case the lug 9 Ais replaced by a lug 27 of moulded insulating materialhavinga socket at its outer end to receive the pick-up. Into the other end of the'l'ug are moulded heads 28 onfthe inner ends of two machined cylindrical'rods v29 which are rigidly held' in 'align ment during the mouldingr process.

The arm 30 which replaces the arm 1 is alsomoulded from-insulating material and thebrackets 31 carrying the vgrooved rollers 32 are secured into place in the moulding operation. Leads from the picklup' 8 are taken to terminals 33 which are connected by `internal leads 34 to the .heads 28'on the rods. Each rod is in metallic contact with one roller 32 and hence with one bracket 31. and leads 35 are taken inside the arm 30 from the `bracketsf31 to iixed'terminals connection means between thef'su'pport and L of a record disc through the point` of "contact with the' discof a stylus carriedby the pick-up and said means permitting `the sup- 5 port tebe rocked in a'plane-at right angles to its-line of travel. i .f

2;-'Ay mounting foran electrical pick-up for gram'ophones' co'mprising a fixed sup- A .the holder, saidmeans vconstraining said support totravel in a path'parallel to a radius port, a holder for a pick-up, and travelling.;

connection meansbetween th'efsupport and the holder vforinedby the co-engagement Aof -V spaced groo'ved rollers withaistraight cfylindric'al rod, whichpermits the holder to rock f about the axis '.'oith'ewrflod and constrainsit to travel in a's'traight line4 parallel tejay vradius of a record disc; passing through the point of contact with the disc ofa stylus, car'- .3. A mounting foran .electrical pick-upi'l'f portinglarm', a fixed lcylindrical-'rod carried. by saidarm, a holderfor a pickup and lto allow the holder to be rotated about the'y Y t p r Y Y ,axiscfpthe rod; the said rod' being parallel Flexible electric Lleadsfromthe. 'pick-up, are

the point of contact with the disc of a stylus carried by the pick-up.

connection meansv between the Vsupport and the holder formed by the co-engagement ofl j i 'spaced grooved rollers with a straight cylindrical rod, said rod being dividedrtransversely into two portions which are electrically insulated from each other and are employed as conductors in an electrical circuit leading from the pick-up to .fixed terminals on the support.

5. A mounting for an electrical pick-up for gramopliones comprising a xed sup-V port, a holder for a pick-up, and travellin connection means between the support an the holder formed by the cpo-engagementlof i spaced grooved rollers with a straight cylin,

drical rod which permits the holder to rock about the axis of the rod andconstrains it to travel in a straight line parallel to a radius of a record disc passing through the point of Contact with the disc-of a styluscarried by the pick-up, an extension on' said holder extending on the side ofthe" rod opposite from the pick-up, and adjustable means on said extension to compensate forl the weight of the pick-up.

tures.

onoIL MONTAGUE WALTER RICHARD GREGORYMARSH.

mounting for an electrical pick-up n for gramophones comprising a fixed sup-.1. v port, a holder for a pick-up,.and travelling In testimony whereof we ax our signa- 

